From: Kiselev, Oleg Date: Wed, 20 Jul 2022 04:27:48 +0000 (+0000) Subject: ext4: avoid resizing to a partial cluster size X-Git-Tag: v5.15.73~810 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=72b850a2a996f72541172e7cf686d54a2b29bcd8;p=platform%2Fkernel%2Flinux-rpi.git ext4: avoid resizing to a partial cluster size [ Upstream commit 69cb8e9d8cd97cdf5e293b26d70a9dee3e35e6bd ] This patch avoids an attempt to resize the filesystem to an unaligned cluster boundary. An online resize to a size that is not integral to cluster size results in the last iteration attempting to grow the fs by a negative amount, which trips a BUG_ON and leaves the fs with a corrupted in-memory superblock. Signed-off-by: Oleg Kiselev Link: https://lore.kernel.org/r/0E92A0AB-4F16-4F1A-94B7-702CC6504FDE@amazon.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin --- diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c index fa3c854..862cbbc 100644 --- a/fs/ext4/resize.c +++ b/fs/ext4/resize.c @@ -1977,6 +1977,16 @@ int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count) } brelse(bh); + /* + * For bigalloc, trim the requested size to the nearest cluster + * boundary to avoid creating an unusable filesystem. We do this + * silently, instead of returning an error, to avoid breaking + * callers that blindly resize the filesystem to the full size of + * the underlying block device. + */ + if (ext4_has_feature_bigalloc(sb)) + n_blocks_count &= ~((1 << EXT4_CLUSTER_BITS(sb)) - 1); + retry: o_blocks_count = ext4_blocks_count(es);